Intrinsically stable Li-ion batteries
| Reference number | |
| Coordinator | MIMSI Materials AB |
| Funding from Vinnova | SEK 500 000 |
| Project duration | May 2016 - February 2017 |
| Status | Completed |
Purpose and goal
The purpose of the project was to demonstrate the possibility of using bespoke thin film coatings based on MIMSI to protect Li-ion battery current collector foils from corrosion, thereby improving device safety, lifetime and performance. An effective anode coating can enable the use of Al as the current collector to improve gravimetric energy density by up to 25%. An effective cathode coating can enable ionic liquids that can dramatically improve battery safety and also increase the nominal operating voltage from 3.6 V to 4.8 V, thereby increasing energy and power density by up to 35%.
Expected results and effects
A MIMSI thin film coating was developed to block lithium from alloying with the battery anode aluminum current collector foil. The coating was evaluated and demonstrated the potential to hinder alloying without negative effects from the carbonate-based electrolyte; however, the protection is not 100% effective. This is likely caused by defects in the film due to Al foil roughness. Data generated showed a strong correlation between increased coating thickness and improved performance. Further coating optimization will be undertaken based on a careful cost/benefit assessment.
Planned approach and implementation
A specification for the coating was developed from customer requirements, information from battery experts and literature searches. Using this as a starting point a coating material was chosen. Coatings of different thicknesses were then deposited on battery grade Al foil under different process conditions. This made it possible to test the reactivity of the coating material and its effectiveness in protecting the Al current collector foil used at the anode.